Method and apparatus for manufacturing tubes



May 23., 1933.: LBECKER lvglo?? METHOD AND APPARATUS FOR MANFACTURING TUBES Filed' March 7, 195o 2 sheets-,sheet 1 'qll/111111111111 q/11M l5 3 o /lrll/l//I//Jlllllllll/.l/l

)Kx f4 i fi @E25 4 H i nvvENToR 22 LM Mn May 23, 1933. L BECKER l'1,910,377

METHOD AND APPARATUS FOR MANUFACTURING TUBES Filed March '7, 1930 2. Sheets-Sheet 2 /NVENTOR La w VM gk dw l" Patented May 23, 1933 LEO BECKER, OF YOUNGSTOWN, OHTO METHOD AND APPARATUS FOR MANUFACTURING TUBES Application led March 7, 1930, Serial No. 434,103, and in Germany March 11, 1930.

This invention relates to the making of pipe or tubes and is particularly directed toward a method and an apparatus for cross rolling whereby the accuracy of the product as to thickness and size may be regularly maintained.

In a cross rolling mill wherein the cross rolls cooperate with a plug or mandrel over which the billet or tube` is shaped to the desired tube form, there is obviously a minimum space between the cross rolls and the mandrel which determines the thickness of the formed tube. The mandrel is necessarily supported on a long rod in order t accommodate the formed tube, and this rod tends to become hotter during rolling. This causes the mandrel to move longitudinally, thus changing its position relative to the cross rolls and aecting the thickness and size of the tube.

I provide for maintaining the relative setting of thecross rolls and the mandrel substantially constant, and preferably accomplish this by adjusting the effective length of the mandrel rod. This adjust-ment is preferably automatic in character. In order to obtain the best results, provision is made f or cooling the mandrel rod so as to minimize changes in length due to temperature or longitudinal forces arising during rolling, butI even the most minute variations in length are compensated for by my improved apparatus.

rovision Xis also made for discharging part of the cooling iiuid into the tube so as to remove scale and dirt therefrom. This materially increases the life of the mandrel, insures greater accuracy of size, and eliminates scratching and pitting of the inside of the tube.

In the accompanying drawings illustrating the present preferred embodiment of the invention and certain modifications thereof,

Figure 1 is a transverse sectional view, partly broken away, showing a cross roll and a cooperating mandrel with means for automatically adjusting the mandrel position;

Figure 2 is a similar view but modified structure; l

Figure 3 is a diagrammatic view illustratshowing a ing a portion of the mechanism of Figure 1; `Figure 4 is a view corresponding to Figure 1, but showing another modification; and

Figure 5 is a View to enlarged scale of a roll pass for enlarging the tube wherein the mandrel rod is under tension. l

Figure 6 is a circuit diagram showing the control system for the invention.

Referring to Figure 1 there is shown a cross roll 2, constituting one ofseveral such rolls 39 forming the pass, and a cooperating mandrel 3. AThe pierced billet is indicated at B and the formed tube is shown at T. The mandrel 3 is supported on a rod 4 having a rear por- .tion 5 socketed in a threaded block 6. A 65 thrust bearing 7 is provided. .The block 6 isthreaded in a fixed nut 8 and carries agear 9 meshing with a pinion l0. The pinion is driven through any suitable gearing by a motor, not shown, and it will benoted that the pinion is of suficientv width to continue in mesh with the gear 9 despite the block 6 being threaded in or out of the nut 8.

The mandrel rod 4 is provided with a central opening 11 through which cooling water 75 may be supplied. This water passes through openings 12 just back ofthe mandrel head to an outer annular passage 13 from which it is discharged at 14. The passage 13 is formed between two sleeves 15 and 16 and 3 the water in the annulus forms an effective cooler and insulator which shields the mandrel rod from the heat of the rolled material.

The annular space 17 between the mandrel rod 4 and the sleeve 15 may be utilized as an 35 air cell which further serves to protect the mandrel rod from the heat of the rolled material, or it may be packed with a suitable insulating material 18, such as kieselguhr, asbestos or the like- 90 Provision is made for adjusting the position of the threaded block 6 so as to maintain the relationship between the cross rolls 2 and the mandrel 3 substantially constant. The mechanism for doing this is indicated diagrammatically in Figure 3, wherein the sleeve 15 is indicated at 15a. From the rear end of this sleeve there projects forwardly a rod 20, which rod, at its forward end, is Connected by a block 21 to a rearwardly exum tending rod 22 having a'lower thermal coefiicient of expansion than the rod 20. The

sleeve a, furthermore, has a lower thermal ".in the rolling pressure one of the contact screws 24 or 25 will contact with its terminal 26, thus closing a circuit to operate the motor 26a which drives the'pinion 10 and threads the block 6 in or out of the block 8 until the contact screws again assume their position intermediate of the contacts 26. The position of the mandrel 3 relative to the cross rolls is thus maintained substantially constant. Changes in the temperature of the mandrel supporting members do vnot cause any change in the position of the mandrel because of the thermal compensation provided. Any changes inthe mandrel position resulting from changes in rolling pressure are immediately compensated by the automatic notor-driven adjusting mechanism.

In Figure 1 I have shown a fluid passage 27 forming an extension of the rod 4 and leading through openings 28` in the head of the mandrel 3 past avalve 29. This valve is spring locked, as indicated at 30, so that by suitable control any desired amount of fluid,l

preferably water, may be fed through the valve to the inside of the pierced billet B. This water eectually washes back the scale, slag and other foreign material in the body of the billet. -The water also acts as a lubricant for the working surface of the mandrel.

In Figure 2 there is shown a modiied construction wherein parts corresponding to Figure 1 have been given the same reference characters with a letter b suiiixed thereto. In this form of the invention water is supplied through the central bore 11b and passes out through an annulus 13b. The control mechanism is similar to that described for Figures 1 and 3, and functions in the same manner. It will be noted that in this embodiment of the invention the mandrel is reversed so that the mandrel rod is under tension instead of compression, but in either case its length is adjusted, and the amount of stretching or shortening occasioned by rolling forces, as well as by reason of temperature changes, is compensated for. A

Referring to Figures 4 and 5, there are shown modified' structures adapted to compensate for changes in the length of the mandrel rod whether the same be under tension or compression. In these forms of the invention -the mandrel rod is indicated at 4a and it is in the form of a hollow tube. A smaller tube 31 is placed within the mandrel rod and is permanently secured thereto just back of the mandrel head, as indicated at 32. The rear end of the tube 31 is free to move and it carries a flange 33 lying between contact screws 34. These screws control a motor, not shown, for driving a worm 35 meshing with worm teeth 36 on a threaded block 37.

The block 37 is threaded in a fixed nut 38 and is rotatable on the mandrel rod 4a. The mandrel rod 4a carries thrust rings 39. It will be seen that the position of thel mandrel relative to the fixed nut 38 is automatically fixed and maintained by the control mechanism which is effective for causing threading of the block 37 into or out of the nut 38 in an amount sufficient to always maintain the flange 33 between the contact points 34 but clear thereof.

Cooling fluid for the mandrel rod is supplied at 40, the fluid travelling through the inner tube 31 and issuing into the-bore of the mandrel rod 4a through openings 41. The Huid travels back through this bore to a space42 and is taken off from the block 37 through passages 43. The tube 31 is maintained at substantially constant temperature by the cooling vluid,'thus insuring the desired delicacy of control.

I have illustratedand described a present preferred embodiment of the invention and certain modifications thereof. It will be understood, however, that it is not limitedto the forms shown but may be otherwise embodied or practiced within the scope of the following claims. The invention may, for example, be employed on tube mills having parallel rolls or on draw benches for tube.

making.

- I claim:

1. Tube making apparatus comprising` a mandrel, a mandrel rod therefor, a control bar extending fromthe vicinity of the mandrel and means controlled thereby for automatically compensating for changes inthe length of said mandrel rod. i

2. A supporting rod for a mandrel of a tube mill, having an axial bore a control rod therein, means for maintaining the control rod at a constant temperature, and means actuating by said control rod on changes in the effective length of the mandrel rod for automatically compensating said changes.

3. In a tube mill, a mandrel-supporting rod, a mandrel at the end of the supporting rod, an electric contact, means responsive to movement of said mandrel for actuating said contact, and means controlled therebyfor adjusting the position of the mandrel.

4. A In a method of working metal, the steps the portion of the billet aproaching the mandrel and rolls.

5. In a method of working metal, the steps including forcing a pierced billet over a man- 5 drel and supplying fluid to the interior of the portion of the billet approaching the mandrel for removing foreign matter therefrom. 6. In a method of making tubes from pierced billets, the steps including rolling a 0 billet over a Amandrel and forcing Huid through the portion of the billet approaching the mandrel to remove foreign matter therefrom.

7. Metal-working apparatus comprising cross rolls, a mandrel cooperating therewith, motor-actuated means for shifting said mandrel with respect to said cross rolls, and electrical contacts operated on a change in the posit-ion of the mandrel for operating said 2 shifting means to restore the mandrel to its initial position.

8. Metal working apparatus comprising cross rolls, a mandrel cooperating therewith, a mandrel rod for supportingthe mandrel motor-driven means for shifting the mandrel rod with respect to said cross rolls, and electric contacts actuated by movement of the mandrel relative to the rolls for operating said shifting means to restore the initial position of the mandrel. 9. Metal working apparatus comprising reducing rolls, a mandrel cooperating therewith, a rod for supporting the mandrel, an abutment for the rod including an adjusting screw, a motor for driving the screw and contacts actuated on movement o the mandrel relative to the rolls for operating said` screw motor to restore the initial position of the mandrel.

..40 In testimony whereof I have hereunto set my hand.

LEO BECKER. 

